The Dorm Gourmet: Ten Tips beyond Microwave Cooking Basics
Whether you’re a college student, beginner or intermediate level cook, your microwave cooking education likely included two lessons: 1) Don’t put metal in it, and 2) Don’t try to cook a whole egg. Unfortunately for many, your microwave training probably stopped there. Cooking in the microwave for most is limited to re-heating coffee, boiling water, and “baking” a potato. It’s a substantial step up to sauté vegetables, bake a cake or cook fish in a kitchenette with no stove, only a few simple tools and a microwave oven.
Microwave ovens heat quickly and preserve the nutritional value of foods better than boiling. You can also cook without adding the large amount of fat necessary for frying. What microwave ovens don’t do well is brown – add crispiness, caramelize sugars to the surface of baked goods and char meats. Along with rice cookers, microwaves are one of the few cooking devices most dorms allow. Besides these strengths and limitations, how do you make better use of your microwave oven?
Ten Tips to Successful Microwave Cooking
1. Foods need moisture. Dry foods don’t heat well in microwaves. Microwave ovens cook by vibrating polar molecules like water. The friction from the vibrations generates heat, microwaves pass through foods with low moisture content. To fix this, add a small amount of water or broth to drier foods to create steam or prepare them for microwaving. Preserve the moisture by cooking in a covered container with a steam vent. When cooking vegetables, wrap them in moistened kitchen (cotton) or paper towels to surround them with steam.
2. Use the power settings to improve evenness. Intuitively, it makes sense to heat at full power all the time to cook faster. Many people don’t realize that the power settings on their ovens don’t change the wattage or intensity of power, just the cooking time. That is, microwave ovens don’t heat at 70% or 30% of their intensity when set at 70% or 30% power, instead the oven cycles between “on” and “off”. Higher settings are “on” more of the total cooking time, lower settings are “off” more of the cooking time. If you extend the cooking time and lower the power setting, the “off” time allows hot spots to radiate to colder areas and avoid overcooked patches.
3. Shape matters – Microwave ovens penetrate about an inch into thick foods. When possible, divide thicker items making them thinner, smaller and flatter. The corners of squares and rectangles will cook faster and potentially burn before the center is done, to correct, select a lower power setting to allow the center of square-shaped foods to catch-up or reshape them into discs.
4. Avoid superheating liquids – When boiling water, heating water for tea or reheating coffee, be aware of superheated fluids, i.e. fluids that are heated slightly beyond their boiling point. Smooth glass containers sometimes won’t form bubbles as the contents heat, so the true temperature isn’t obvious. This can lead to dangerous eruptions when adding sugar, salt or even a metal spoon (see video below). The best solution is to learn how long it takes to heat beverages and not exceed that time.
The Danger of Superheating in Microwaves
5. Microwave ovens cook from the top. Because the microwaves cook from the top down, don’t stack foods. Stir, flip and move items around midway through cooking to even-out inconsistent heating.
6. Salt. Salty foods tend to cook faster. Be careful to not add excess salt to the surface of foods; salt draws moisture out of items. Pre-soaking foods in brine can increase the water content of foods and speed up the cooking.
7. Use the right materials. Make sure that all of your microwave cooking dishes and containers are explicitly labeled “microwave safe”. Don’t assume a container is safe until you see that label. Parchment paper is a good choice, most types are microwave safe. Many containers that are perfectly food safe under other conditions don’t hold up to microwaves: most plastics are made from petroleum; many ceramics have glazes that contain toxins. Below is a list of items NOT suitable for microwaves:
- Metal, especially look for small staples in tea bags, take-out container handles, gold leaf on china, foil wrappers.
- Plastic food wraps may be safe as covers, but shouldn’t touch the food directly during heating.
- Re-sealable plastic bags.
- Paper bags and newspapers are not sanitary, often made of recycled materials of unknown origins and contain glues that are toxic when heated in a microwave oven.
- Plastic margarine tubs, take-out. deli containers or ice cream containers.
- Grapes and uncut fruit.
8. Open, Pierce, or Vent – Any type of sealed container should be cracked or opened slightly before going into a microwave oven to prevent a small explosion. For the same reason, foods with skins and microwaveable frozen foods with film coverings should be piered.
9. Use a food thermometer to identify hot and cold spots. A good, instant read thermometer may seem like an extravagance to a beginner cook with few other tools, but microwaves are famous for uneven cooking. To eliminate the guesswork, splurge on a $25 - $35 thermometer, learn safe cooking temperatures and use it regularly to ensure hot foods are hot and thoroughly cooked.
10. Find out the wattage of your microwave oven which should be easy to find on or near the oven door. Recipes written for microwave cooking will often specify a wattage when giving cooking times. Generally speaking, smaller and older microwave ovens have lower wattages, e.g. 600 – 900. If a recipe doesn’t specify wattage, assume a lower wattage. Larger, newer ovens are typically 1000 – 1200 watts. If you can’t find it on the microwave, you can likely find it online at the manufacturer’s website.